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Dynamic recrystallization mechanism, texture evolution development and mechanical characteristics of a Mg–8.7Gd–4.18Y–0.42Zr magnesium alloy by ECAP

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Progress in natural science:Materials International 2024年第02期34卷 376-388页

作者： Ling Zhang Yinglong Li School of Materials science and Engineering Northeastern University School of Mechanical and Engineering Ningxia Institute of Science and Technology

Equal channel angle pressing is recognized for its ability to refine alloy grains and alter grain orientation, thereby achieve better mechanical performance of the magnesium alloy. This study investigates the microstructures,dynamic recrystallization mechanism, texture development, and mechanical performance of GW94K(Mg–8.7Gd–4.18Y–0.42Zr wt. %) Mg alloy following ECAP-4 passes at 400°C and 3 mm/min. Results show that when high-temperature deformation is undertaken, twin formation is suppressed while dislocation slip is facilitated, increasing dislocation density during deformation. Following ECAP deformation, the sample displayed higher fracture elongation, TYS, and UTS than the as-solutioned GW94K alloy. In particular, the GW94K alloy performed well mechanically after ECAP-4 passes, with an ultimate TYS of 231 MPa, an UTS of 290 MPa, and an elongation of 14.8 %. DDRX and shear bands induce CDRX, both of which are important in plastic deformation. as well as in modifying microstructure and grain orientation during ECAP deformation.

关键词： Dynamic recrystallization mechanism Equal channel angular pressing Magnesium alloy Mechanical performance Mg-Gd-Y-Zr alloy Texture development

Asymptotic behavior of an SIQR epidemic model driven by Lévy jumps on scale-free networks

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International Journal of Biomathematics 2024年第2期17卷 51-86页

作者： Yuncheng Xu Sanyang Liu Xiaojun Sun Hua Hu Yu Wang School of Mathematics and Statistics Xidian University Xi'an 710071P.R.China School of Mathematics and Statistics Ning Xia University Ningria 750021P.R.China School of Mathematics and Information science Bao Ji University of Arts and sciences Baoji 721013 P.R.China College of Mathematics science and Center for Applied Mathematical science Inner Mongolia Normal University Hohhot 010022 P.R.China

To investigate the effect of information transmission,Levy jumps and contact heterogeneity of individuals on the asymptotic behavior of epidemic,a stochastic SIQR epidemic model with non-monotone incidence rate and Levy jumps on scale-free networks is *** first,the global dynamics of the deterministic model is studied by constructing appropriate Lyapunov *** the stochastic model is made in accordance with the ecological significance,the existence and uniqueness of the global positive solution of the stochastic SIQR model is ***,by constructing suitable stochastic Lyapunov functions and applying Ito formula with jump,the asymptotic behavior of solutions of stochastic model around equilibrium of the corresponding deterministic model is *** last,the correctness of the analytical results is verified by numerical simulations.

关键词： Lévy jumps asymptotic behavior non-monotone incidence rate scale-free networks SIQR.

MSD-Net: Pneumonia Classification Model Based on Multi-Scale Directional Feature Enhancement

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Computers, Materials & Continua 2024年第6期79卷 4863-4882页

作者： Tao Zhou Yujie Guo Caiyue Peng Yuxia Niu Yunfeng Pan Huiling Lu School of Computer science and Engineering North Minzu UniversityYinchuan750021China School of Medical Information&Engineering Ningxia Medical UniversityYinchuan750004China Key Laboratory of Image and Graphics Intelligent Processing of State Ethnic Affairs Commission North Minzu UniversityYinchuan750021China

Computer-aided diagnosis of pneumonia based on deep learning is a research ***,there are some problems that the features of different sizes and different directions are not sufficient when extracting the features in lung X-ray images.A pneumonia classification model based on multi-scale directional feature enhancement MSD-Net is proposed in this *** main innovations are as follows:Firstly,the Multi-scale Residual Feature Extraction Module(MRFEM)is designed to effectively extract multi-scale *** MRFEM uses dilated convolutions with different expansion rates to increase the receptive field and extract multi-scale features ***,the Multi-scale Directional Feature Perception Module(MDFPM)is designed,which uses a three-branch structure of different sizes convolution to transmit direction feature layer by layer,and focuses on the target region to enhance the feature ***,the Axial Compression Former Module(ACFM)is designed to perform global calculations to enhance the perception ability of global features in different *** verify the effectiveness of the MSD-Net,comparative experiments and ablation experiments are carried *** the COVID-19 RADIOGRAPHY DATABASE,the Accuracy,Recall,Precision,F1 Score,and Specificity of MSD-Net are 97.76%,95.57%,95.52%,95.52%,and 98.51%,*** the chest X-ray dataset,the Accuracy,Recall,Precision,F1 Score and Specificity of MSD-Net are 97.78%,95.22%,96.49%,95.58%,and 98.11%,*** model improves the accuracy of lung image recognition effectively and provides an important clinical reference to pneumonia Computer-Aided Diagnosis.

关键词： Pneumonia X-ray image ResNet multi-scale feature direction feature transformer

Iron-nickel alloy particles with N-doped carbon “armor” as a highly selective and long-lasting catalyst for the synthesis of Nbenzylaniline molecules

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Nano Research 2024年第4期17卷 2308-2319页

作者： Gang Wang Longchao Sun Wanyi Liu Haijuan Zhan Shuxian Bi College of Chemistry and Chemical Engineering Ningxia UniversityYinchuan 750021China

A scalable strategy for the convenient and rapid preparation of nitrogen-doped carbon-coated iron-based alloy catalysts was *** controlling the type and amount of metal salts in the precursor,various types of nitrogen-doped carbon-coated alloy catalysts can be prepared in a targeted ***_(2)Ni2@CN materials with small particle sizes and relatively homogeneous basic sites showed promising results in the N-alkylation reaction of benzyl alcohol with aniline(optimum yield:99%).It is worth noting that the catalyst can also be magnetically separated and recovered after the reaction,and its performance can be regenerated through simple ***,it was confirmed by kinetic experiments that the activation of C–H at the benzyl alcohol benzylic position is the rate-determining step(RDS).According to density flooding theory calculations,Fe_(2)Ni2@CN catalysts require less energy than other materials(Fe@CN and Ni@CN)for the RDS(dehydrogenation reaction)*** N-alkylation reactions are more easily carried out on Fe_(2)Ni2@CN catalysts,which may be the reason for the best catalytic activity of Fe-Ni alloy *** carbon-coated alloy materials will show great potential in more types of heterogeneous catalysis.

关键词： iron-nickel alloy catalyst N-alkylation reaction magnetic separation reaction path dehydrogenation reaction

Response of ecosystem carbon storage to land use change from 1985 to 2050 in the ningxia Section of Yellow River Basin,China

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Journal of Arid Land 2024年第1期16卷 110-130页

作者： LIN Yanmin HU Zhirui LI Wenhui CHEN Haonan WANG Fang NAN Xiongxiong YANG Xuelong ZHANG Wenjun College of Geographical sciences and Planning Ningxia UniversityYinchuan 750021China China-Arab Joint International Research Laboratory for Featured Resources and Environmental Governance in Arid Region Yinchuan 750021China ningxia Land Resources Surveying and Monitoring Institute Yinchuan 750002China State Key Laboratory of Efficient Production of Forest Resources Yinchuan 750002China ningxia Lingwu Baijitan National Nature Reserve Administration Yinchuan 751400China

Regional sustainable development necessitates a holistic understanding of spatiotemporal variations in ecosystem carbon storage(ECS),particularly in ecologically sensitive areas with arid and semi-arid *** this study,we calculated the ECS in the ningxia Section of Yellow River Basin,China from 1985 to 2020 using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model based on land use *** further predicted the spatial distribution of ECS in 2050 under four land use scenarios:natural development scenario(NDS),ecological protection scenario(EPS),cultivated land protection scenario(CPS),and urban development scenario(UDS)using the patch-generating land use simulation(PLUS)model,and quantified the influences of natural and human factors on the spatial differentiation of ECS using the geographical detector(Geodetector).Results showed that the total ECS of the study area initially increased from 1985 until reaching a peak at 402.36×10^(6) t in 2010,followed by a decreasing trend to *** spatial distribution of ECS was characterized by high values in the eastern and southern parts of the study area,and low values in the western and northern *** 1985 and 2020,land use changes occurred mainly through the expansion of cultivated land,woodland,and construction land at the expense of unused *** total ECS in 2050 under different land use scenarios(ranked as EPS>CPS>NDS>UDS)would be lower than that in *** light was the largest contributor to the spatial differentiation of ECS,with soil type and annual mean temperature being the major natural driving *** of this study could provide guidance on the ecological construction and high-quality development in arid and semi-arid areas.

关键词： carbon storage land use change nighttime light Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model patch-generating land use simulation(PLUS)model geographical detector(Geodetector) Yellow River Basin

Frictional contact analysis of a rigid solid with periodic surface sliding on the thermoelectric material

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 179-196页

作者： Yali ZHANG Yueting ZHOU Shenghu DING School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China

Understanding and characterizing rough contact and wavy surfaces are essential for developing effective strategies to mitigate wear,optimize lubrication,and enhance the overall performance and durability of mechanical *** sliding friction contact problem between a thermoelectric(TE)half-plane and a rigid solid with a periodic wavy surface is the focus of this *** simplify the problem,we utilize mixed boundary conditions,leading to a set of singular integral equations(SIEs)with the Hilbert *** analytical solutions for the energy flux and electric current density are obtained by the variable transform method in the context of the electric and temperature *** contact problem for the elastic field is transformed into the second-kind SIE and solved by the Jacobi ***,the smoothness of the wavy contact surface ensures that there are no singularities in the surface contact stress,and ensures that it remains free at the contact *** on the plane strain theory of elasticity,the analysis primarily examines the correlation between the applied load and the effective contact *** distribution of the normal stress on the surface with or without TE loads is discussed in detail for various friction ***,the obtained results indicate that the in-plane stress decreases behind the trailing edge,while it increases ahead of the trailing edge when subjected to TE loads.

关键词： wavy surface periodic contact thermoelectric(TE)material Hilbert integral kernel

To explore the mechanism of Yigong San anti-gastric cancer and immune regulation

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1965-1994页

作者： Dou-Dou Lu Ling Yuan Zhao-Zhao Wang Jian-Jun Zhao Yu-Hua Du Na Ning Guo-Qing Chen Shi-Cong Huang Yi Yang Zhe Zhang Yi Nan School of Clinical Medicine Ningxia Medical UniversityYinchuan 750004Ningxia Hui Autonomous RegionChina College of Pharmacy Ningxia Medical UniversityYinchuan 750004Ningxia Hui Autonomous RegionChina Traditional Chinese Medicine College Ningxia Medical UniversityYinchuan 750004Ningxia Hui Autonomous RegionChina Department of Chinese Medical Gastrointestinal China-Japan Friendship HospitalBeijing 100029China Key Laboratory of ningxia Minority Medicine Modernization Ministry of Education Ningxia Medical UniversityYinchuan 750004Ningxia Hui Autonomous RegionChina

BACKGROUND Yigong San(YGS)is a representative prescription for the treatment of digestive disorders,which has been used in clinic for more than 1000 ***,the mechanism of its anti-gastric cancer and regulate immunity are still remains *** To explore the mechanism of YGS anti-gastric cancer and immune *** Firstly,collect the active ingredients and targets of YGS,and the differentially expressed genes of gastric ***,constructed a protein-protein interaction network between the targets of drugs and diseases,and screened hub *** the clinical relevance,mutation and repair,tumor microenvironment and drug sensitivity of the hub gene were ***,molecular docking was used to verify the binding ability of YGS active ingredient and hub *** Firstly,obtained 55 common targets of gastric cancer and *** Kyoto Encyclopedia of Genes and Genomes screened the microtubule-associated protein kinase signaling axis as the key pathway and IL6,EGFR,MMP2,MMP9 and TGFB1 as the hub *** 5 hub genes were involved in gastric carcinogenesis,staging,typing and prognosis,and their mutations promote gastric cancer ***,molecular docking results confirmed that the components of YGS can effectively bind to therapeutic *** YGS has the effect of anti-gastric cancer and immune regulation.

关键词： Gastric cancer Yigong San Mechanism Immune

Synergistic effect of Co and Co_(6)Mo_(6)C for electroreduction of nitrate to ammonia on Co-MOF derived Co_(6)Mo_(6)C/Co/NC

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Nano Research 2024年第7期17卷 5807-5816页

作者： Xinyan Wang Yue Cao Yan Hai Xiaoman Li Min Luo State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering School of Chemistry and Chemical EngineeringNingxia UniversityYinchuan 750021China

Electrocatalytic nitrate reduction reaction(e-NO_(3)RR)offers a promising alternative method for nitrogen cycling and ammonia(NH3)production under ambient ***,the method is still in the dilemma of lowering the reaction overpotential and increasing the reaction *** successfully developed the composition-adjustable Co_(6)Mo_(6)C/Co/N-doped carbon(NC)catalysts by in situ carbonization of Co-based metal-organic framework(MOF)with the constrained phosphomolybdic *** adjusting the ratio of Co0 and Co_(6)Mo_(6)C,Co_(6)Mo_(6)C/Co/NC-3 could satisfy both NO_(3)−conversion at low potential and NH_(x)hydrogenation,and synthesize ammonia efficiently through the synergistic effect of Co0 and Co_(6)Mo_(6)*** achieved an ammonia yield rate as 1233.2μg·h^(−1)·mgcat^(−1)and Faradaic efficiency of NH4+93.6%at−0.33 V *** hydrogen electrode(RHE).Importantly,density functional theory(DFT)calculations and experimental results have demonstrated for the first time the excellent adsorption of nitrite(NO_(2)^(−))by the Mo sites of Co_(6)Mo_(6)C during e-NO_(3)RR,avoiding the undesirable accumulation of NO_(2)^(−).

关键词： synergistic effect nitrate electroreduction Co_(6)Mo_(6)C ammonia synthesis

Effects of wind speed,underlying surface,and seed morphological traits on the secondary seed dispersal in the Tengger Desert,China

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Journal of Arid Land 2024年第4期16卷 531-549页

作者： QU Wenjie ZHAO Wenzhi YANG Xinguo WANG Lei ZHANG Xue QU Jianjun Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwestern China of Ministry of Education Ningxia UniversityYinchuan 750021China University of Chinese Academy of sciences Beijing 100049China School of Ecology and Environment Ningxia UniversityYinchuan 750021China

The maintenance of sand-fixing vegetation is important for the stability of artificial sand-fixing systems in which seed dispersal plays a key *** on field wind tunnel experiments using 11 common plant species on the southeastern edge of the Tengger Desert,China,we studied the secondary seed dispersal in the fixed and semi-fixed sand dunes as well as in the mobile dunes in order to understand the limitations of vegetation regeneration and the maintenance of its *** results indicated that there were significant variations among the selected 11 plant species in the threshold of wind speed(TWS).The TWS of Caragana korshinskii was the highest among the 11 plant species,whereas that of Echinops gmelinii was the *** morphological traits and underlying surface could generally explain the *** the secondary seed dispersal processes,the proportions of seeds that did not disperse(no dispersal)and only dispersed over short distance(short-distance dispersal within the wind tunnel test section)were significantly higher than those of seeds that were buried(including lost seeds)and dispersed over long distance(long-distance dispersal beyond the wind tunnel test section).Compared with other habitats,the mobile dunes were the most difficult places for secondary seed *** seeds were the easiest to be found in the semi-fixed sand dunes,whereas fixed sand dunes were the best sites for seeds that dispersed over long *** results of linear mixed models showed that after controlling the dispersal distance,smaller and rounder seeds dispersed *** index and wind speed were the two significant influencing factors on the burial of *** explanatory power of wind speed,underlying surface,and seed morphological traits on the seeds that did not disperse and dispersed over short distance was far greater than that on the seeds that were buried and dispersed over long distance,implying that the processes and mechanisms of burial and lo

关键词： seed dispersal seed morphological traits wind speed vegetation regeneration wind tunnel Tengger Desert